Table 2.
Basic characteristics of the study population across quintiles of SBP variability
| Characteristics a | Overall |
Quintile of SBP variability |
|||||
|---|---|---|---|---|---|---|---|
| (n=1,835) | Q1 (n=367) | Q2 (n=366) | Q3 (n=367) | Q4 (n=368) | Q5 (n=367) | P value | |
| Age at baseline, years | 71.0 (6.4) | 70.4 (6.2) | 70.1 (6.0) | 71.1 (6.4) | 71.4 (6.5) | 72.0 (6.5) | <0.001 |
| Women, % | 62.5 | 56.1 | 62.0 | 64.0 | 62.8 | 67.5 | 0.003 |
| SBP (mmHg) | 144 (21) | 146 (21) | 142 (19) | 142 (19) | 144 (22) | 144 (21) | 0.96 |
| DBP (mmHg) | 76 (11) | 79 (12) | 76 (10) | 76 (10) | 76 (11) | 75 (11) | <0.001 |
| Total cholesterol, mmol/L | 5.9 (0.9) | 5.9(1.0) | 6.0(1.0) | 5.9(0.9) | 5.9(1.0) | 6.0(0.9) | 0.85 |
| HDL cholesterol, mmol/L | 1.4 (0.4) | 1.4(0.4) | 1.4(0.4) | 1.4(0.4) | 1.4(0.4) | 1.4(0.4) | 0.20 |
| APOEgenotype, % | 0.91 | ||||||
| ε3/ε3 | 59.1 | 58.6 | 58.1 | 59.6 | 61.8 | 57.5 | - |
| ε2/ε2 or ε2/ε3 | 13.8 | 14.6 | 14.8 | 14.2 | 13.5 | 11.9 | - |
| ε2/ε4 or ε3/ε4 | 25.0 | 25.7 | 23.7 | 24.0 | 23.1 | 28.3 | - |
| ε4/ε4 | 2.1 | 1.1 | 3.4 | 2.2 | 1.6 | 2.2 | - |
| Education, % | 0.03 | ||||||
| Primary/intermediate | 89.3 | 87.7 | 88.4 | 89.0 | 87.6 | 93.6 | - |
| Higher education | 10.7 | 12.3 | 11.6 | 11.0 | 12.4 | 6.4 | - |
| Smoking status, % | 0.63 | ||||||
| Never | 34.4 | 33.5 | 34.3 | 39.9 | 27.5 | 36.6 | - |
| Past | 47.7 | 48.4 | 49.7 | 42.6 | 54.5 | 43.3 | - |
| Current | 17.9 | 18.1 | 16.0 | 17.5 | 17.9 | 20.1 | - |
| Weight status, % b | 0.25 | ||||||
| Normal weight | 34.2 | 31.1 | 33.1 | 35.8 | 33.2 | 37.8 | - |
| Overweight | 46.6 | 51.0 | 43.9 | 44.3 | 46.6 | 47.1 | - |
| Obese | 19.2 | 18.0 | 23.1 | 19.9 | 20.2 | 15.1 | - |
| History of Diabetes, % | 12.0 | 12.4 | 13.3 | 9.2 | 14.0 | 10.9 | 0.70 |
| History of Hypertension, % | 65.8 | 70.5 | 62.6 | 63.8 | 64.1 | 67.8 | 0.60 |
| Antihypertensive medication, % | 31.2 | 35.2 | 26.8 | 31.1 | 31.0 | 31.8 | 0.73 |
Abbreviations: SBP=systolic blood pressure; DBP=diastolic blood pressure; HDL=high-density lipoproteins; APOE= Apolipoprotein E. Data are shown in the format of means (SD) or percentages.
a
Characteristics at baseline (i.e. the third examination between 1997 and 1999 when continuous BP measurements were taken).
b
Weight status was assessed by body mass index (BMI), with overweight defined as 25≤ BMI <30 kg/m2 and obesity defined as BMI ≥30 kg/m2.